Abstract: Aliphatic alcohols are disclosed for promoting corneal healing following injury to the eye. Such compositions ameliorate corneal discomfort, alleviate visual artifacts, and/or reduce irritation caused by the eye injury. The compositions also promote the regrowth of epithelial tissue over the corneal surface.

Abstract: Ultrasound generating methods and apparatus are disclosed for producing controlled, localized hyperthermia in a selected heating zone of human tissue, utilizing at least one ultrasound transducer, preferably driven by sinusoidal excitation signals in a continuous wave or quasi-continuous wave mode to generate ultrasound. The temperature in the heated zone can be controlled by selecting the power, duration and frequency of the ultrasound. The penetration of the ultrasound, and thus the depth and volume of the target zone, can be controlled by selecting the excitation frequencies so to confine the absorption of the ultrasound beam in the target tissue. The invention is particularly useful in inducing controlled collagen shrinkage in corneal tissue to effective thermokeratoplasty (heat induced modification of the shape of the cornea).

Abstract: Aliphatic alcohols are disclosed for the treatment of discomfort and visual artifacts following laser surgical procedures on the cornea of the eye. Such compositions reduce the inflammation associated with photorefractive keratectomy and promote the regrowth of epithelial tissue over the reprofiled corneal surface.

Abstract: Plastic or polymeric materials can be rendered substantially more practical for use in gas laser systems, and the problem of gas contamination due to outgassing of volatile materials can be significantly reduced by coating the polymeric elements with a thin dielectric film.

Abstract: Methods and apparatus for determining the depth of excision generated by a material removal process, for determining the thickness of unablated material below the excision or incision, and for providing endpoint control of a material removal process utilize acoustic transducers for measuring the time delay between a first acoustic pulse resulting from material removal and a second acoustic pulse reflected from a distal surface or boundary layer of the material. The time delay between the two pulses detected by the transducer provides a measure of excision depth and of the depth of material below the excision. Endpoint control is provided by terminating material removal when a selected excision depth is detected. The invention can be used, for example, as a real-time monitor of excision depth and residual lamella thickness under the excision during laser corneal surgery.

Abstract: Disclosed is an apparatus and method for the modifying the intensity profile of radiant energy beam or reducing its spatial coherence, especially that produced by a laser. The apparatus includes a waveguide having a light reflecting surface including a substructure. The light reflecting surface and substructure reflect incident light causing chaotic scattering which acts to homogenize the intensity profile of the laser beam.

Abstract: Aliphatic alcohols are disclosed for the treatment of discomfort and visual artifacts following laser surgical procedures on the cornea of the eye. Such compositions reduce the inflammation associated with photorefractive keratectomy and promote the regrowth of epithelial tissue over the reprofiled corneal surface.

Abstract: The present invention encompasses a high voltage switch utilizing first and second terminal electrodes and an intermediate electrode disposed therebetween. A high voltage pulse, applied to the intermediate electrode, initiates sequential overvoltaging of the region between one of the terminal electrodes and the intermediate electrode and, then between the intermediate electrode and the other electrode; thereby permitting electrical current to flow between the terminal electrodes. The geometry of the electrodes is chosen so as to yield a field enhancement factor between each region which is sufficiently low to permit highly reliable, predictable, and controllable sequential electrical breakdown.

Abstract: A laser system for reprofiling a surface comprising a laser and an erodable mask disposed between the laser means and the surface for providing a predefined profile of resistance to erosion by laser radiation, and control for controlling the laser such that upon irradiation of the mask, a portion of the laser radiation is selectively absorbed and another portion is transmitted to the surface in accordance with the mask profile to selectively erode the surface. The mask can be connected to the support structure and disposed in optical alignment with the laser means and the cornea. The mask can be directed integrated with the support structure or, preferably, a transparent stage can be formed as part of the support structure to support and position the masking lens. In one preferred embodiment, the mask is spatially separated from the surface and imaged onto the surface, thereby permitting the use of an oversized mask, which is easier to form.

Abstract: A laser system and masking apparatus for reprofiling surfaces, such as corneal surfaces. The system includes a laser and a mask disposed between the laser and the surface to be reprofiled, the mask providing a pre-defined profile of resistance to laser radiation, such that upon irradiation, part of the radiation is selectively absorbed and part is transmitted to the surface in accordance with the masked profile, to selectively erode the surface. The masking apparatus may consist of a mask to be affixed to the surface or may further include a support structure to support and position the mask above the surface. The resistance profile can be created by varying the thickness or the composition of the mask.

Abstract: Laser apparatus for eroding a surface comprises means to select and control the shape and size of the area irradiated by each pulse of laser energy without varying the energy density of the beam. By varying the size of the irradiated area between pulses, some regions of the surface may be eroded more than others and so the surface may be reprofiled. The method and apparatus are suitable, inter alia, for removing corneal ulcers and reprofiling the cornea to remove refractive errors and also for reprofiling optical elements. In one embodiment the beam from the laser enters an optical system housed in an articulated arm and terminating in an eyepiece having a suction cup for attachment to an eye. The optical system includes a beam forming arrangement to correct an asymmetric beam cross-section, a first relay telescope, a beam dimensional control system and a second relay telescope.

Abstract: A laser therapy system having improved effectiveness in surgical use, particularly in laser angioplasty, can be formed by employing a pulsed source of radiation. The pulsed energy source is preferably an excimer laser having a coherent beam of ultraviolet radiation and preferably is employed in conjunction with a dye laser to produce an output beam which is tunable over a wide portion of the ultraviolet and visible spectrum. The output beam is coupled via a novel coupling device to an optical fiber disposed within a surgical instrument, for example, a percutaneous catheter. The operative components are sealed in a gas-tight, liquid-tight housing. An electronic controller monitors and adjusts the output energy density, duration, and pulse repetition rate. In operation, a pulsed, high energy beam of extremely short duration is available to remove atherosclerotic plague with less damage to the underlying tissue and less chance of perforating the blood vessel wall.

Abstract: A laser system for reprofiling a surface (18) comprising a laser (10) and an erodible mask (14) disposed between the laser and the surface (18) for providing a predefined profile of resistance to erosion by laser radiation, and a controller (22) for controlling the laser such that upon irradiation of the mask (14), a portion of the laser radiation is selectively absorbed and another portion is transmitted to the surface in accordance with the mask profile to selectively erode the surface. The mask can further comprise a rigid structure (30) which is affixed to the surface, in particular to the sclera of an eye, and a masking lens (36) connected to the support structure and disposed above the cornea. The masking lens can be directed integrated with the support structure or, preferably, a transparent stage (34) can be formed as part of the support structure to support and position the masking lens.

Abstract: Laser-to-waveguide coupling devices and methods are disclosed employing an aperture, and an imaging lens. The aperture clips the beam edges to flatten the spatial intensity profile, and the lens mirror-images the plane of the aperture onto the waveguide face with appropriate magnification or demagnification to match the input beam dimensions to those of the waveguide. In one preferred embodiment, a first focusing lens is also employed in conjunction with a pinhole aperture and a second imaging lens. The first focusing lens focuses the laser beam onto the aperture and thereby reduces the optical path length. The second imaging lens images the plane of the aperture onto the waveguide.

Abstract: A laser system is disclosed in which the laser medium is operated at high pressures, for example, at pressures of about 3 atmospheres or above, to yield high performance. High pressure operation is achieved by employing a two or more stage containment system. In one preferred embodiment, a first containment system, housing high voltage components, can be pressurized to about 2 atmospheres or more with a high dielectric constant gas to permit low inductance circuitry. The laser head assembly is encased within a second containment vessel and further pressurized to about 3 atmospheres or more. The laser head assembly can also include a flow nozzle and ventilated electrodes to reduce stagnant pockets and eddy currents in the circulating laser medium.

Abstract: A laser excitation system is disclosed in which the laser medium is preionized by a UV-generating spark array and is excited by an electric avalanche discharge. The preionized state is sustained during the discharge by a second spark array and an isolated discharge capacitance. In this manner, a continuous ionization state during discharge is achieved.